Do you know how to finish that quest for Junior Agent? Because obviously, I'm not really Japanese but I play the JP server because there is no server in our country

I don't know what is being asked, and I think it is not dungeon because there is no "EASY", "NORMAL", "HARD".. I see it is 6/10 but I played almost all the dungeons available for me and it is still 6/10
I can't even find it in Google or in this forum